Question: Gabriela was assigned problems 30 through 51 for homework tonight. If Gabriela did all of the problems she was assigned, how many problems did she do?
Solution: Instead of counting problems 30 through 51, we can subtract 29 from each number so we instead consider problems 1 through 22. We see that Gabriela did 22 problems. Notice that she did 22 and not 21 problems.